对于未经训练的人来说， SIM 卡(SIM cards)和 SD 卡确实看起来很相似。这两种卡都用于移动电话和其他移动设备。然而，它们有不同的历史、目的和功能。
SIM 和 SD 卡的基础知识
SIM卡(SIM)或用户身份模块(Subscriber Identity Module)是一种微芯片，可安全地存储您的手机号码和蜂窝网络订阅数据。
它允许移动电话在GSM(GSM)蜂窝网络上拨打电话、发送短信 ( SMS ) 以及使用数据服务。手机(Mobile)有专用的SIM卡插槽，卡的尺寸可以从全尺寸SIM卡到nano SIM卡。
SD 卡是安全数字卡(Secure Digital)的缩写，是一种闪存卡，用作数字数据的附加存储。SD 卡的范围从标准 SD 到 microSD 或（很少使用）miniSD。它们存在于各种电子设备中，包括Android智能手机、数码相机以及(Android)任天堂 3DS(Nintendo 3DS)和Switch等游戏机。
SIM卡和SD卡的主要区别在于其功能。SIM卡为您的设备提供身份信息，使其能够拨打电话和发送(SIM)短信。相比之下，SD卡本质上是一种便携式驱动器，可以插入各种电子设备中来存储数据。
虽然某些设备对每种卡类型都有单独的插槽，但其他设备（尤其是智能手机）可以使用组合插槽。例如，某些Samsung Galaxy型号通常具有混合插槽，您可以在其中放置两张SIM卡（双SIM功能）或一张SIM卡和一张 microSD 卡以提供额外存储空间。然而，这并不意味着SIM或 SD 卡有任何共同点，因为这些混合插槽只是使用巧妙的工程设计来集成两种离散标准。
现在我们已经对 SD 和SIM卡有了很好的了解，让我们依次仔细了解一下。
SIM 卡：移动连接(Mobile Connectivity)的关键(Key)
SIM卡就像手机的护照。(SIM)它可以在移动网络上识别您的身份，让您可以拨打电话、发送短信(SMS)或使用WhatsApp等需要手机号码的应用程序。该微型芯片包含一个国际移动用户识别(International Mobile Subscriber Identity)码（IMSI）以及用于加密语音和数据流量的密钥。
SIM卡没有照片、视频或应用程序的存储空间。(SIM)但是，它确实会存储特定信息，例如您的电话号码、短信(SMS)和联系人，具体取决于手机的设置和移动网络。
SIM卡有四种尺寸：全尺寸、Mini SIM、micro SIM卡和 nano SIM卡。
现在，您所想到的“全尺寸” SIM 卡(SIM)很可能是错误的！这些信用卡大小的SIM 卡(SIMs)已不再使用，您仍会看到的最大SIM卡尺寸是(SIM)Mini SIM，但即便如此，这种情况也越来越罕见。通常购买 3 合 1 SIM套餐。如今，一张卡内置了迷你、微型和纳米SIM 卡(SIM)尺寸。您只需划分出您的设备所需的尺寸即可。由于微芯片技术的进步，nano SIM 的金属触点周围几乎没有塑料材料。(SIM)
多亏了这些现代的 Nano SIM 卡，才有可能拥有紧凑的双卡手机。这意味着您可以在同一设备上拥有两个不同的电话号码或移动网络订阅；对于经常出差或同时处理工作和个人号码的人来说，这是一个方便的功能。
SD 卡：您的移动数据仓库
SD卡的主要功能是数据存储。它充当设备内部存储的扩展，为您的文件提供额外的存储容量。您可以使用它在Android(Android)手机或其他使用 SD 卡技术的设备（例如相机）
上存储照片、视频、应用程序和其他内容等数据。
与SIM(SIM)卡不同，SD 卡不提供网络功能或存储您的手机号码。它的唯一目标是提供额外的存储空间。这就是为什么当您获得新手机时，如果您将所有应用程序和媒体文件存储在 SD 卡上，则可以无缝传输它们。
SD 卡有各种存储大小，从几 GB 到高达 1 TB 或更大。SanDisk等领先品牌提供一系列 SD 卡，可从Amazon等零售商在线购买。
SD 卡也有不同的格式。全尺寸 SD 卡通常用于数码相机和笔记本电脑，而 microSD 卡则更常见于手机等小型设备。没有 SD 卡插槽的设备仍然可以使用USB(USB)读卡器访问 SD 卡数据，前提是它们具有必需的USB端口。
(SIM)Android和 iOS 手机中的SIM和SD 卡支持(SD Card Support)
对于Android手机，SIM和 microSD 卡经常一起使用。这意味着您不必太担心购买您能买得起的
最大容量的Android手机，因为您随时可以扩展存储空间。(Android)
另一方面，SD 卡的可靠性远不如手机的内部存储，当您无力承担时，SD 卡就会自发发生故障。(SD card failure)所以一定要做好备份！
Apple iPhone 略有不同。iPhone 还使用SIM卡来提供网络功能。但它们不使用 microSD 卡进行额外存储，而是仅依赖内部存储。这种设计选择就是为什么您在购买 iPhone 时必须仔细选择存储容量的原因。从好的方面来说，尽管苹果(Apple)对更大的存储容量收取了很高的费用，但您将获得比 SD 卡更高的可靠性和速度。
从手机到其他设备
SIM卡主要与手机相关，而 SD 卡的应用范围更广泛。例如，数码相机通常使用全尺寸 SD 卡存储高分辨率照片和视频。Nintendo Switch等游戏机使用(Game)microSD 卡来扩展游戏和保存数据的存储空间。
此外，一些电子设备使用SD卡进行操作。一个典型的例子是Raspberry Pi ，这是一种深受(Raspberry Pi)DIY爱好者和教育工作者欢迎的微型计算机，它使用SD卡来存储操作系统和程序文件。
当然，您会在手机以外的设备中找到 SIM 卡。这包括USB蜂窝调制解调器、具有内置蜂窝功能的笔记本电脑、具有蜂窝访问功能的 iPad，甚至索尼 Vita(Sony Vita)也具有蜂窝模型。
eSims：SIM 卡的终结？
SIM卡已经从信用卡大小发展到微小的纳米尺寸，现在可能变得基本上看不见。我们正在见证从物理SIM(SIM)卡到最新技术创新——e SIM或嵌入式SIM的转变。
那么，e SIM到底是什么？它是一个小型的、不可拆卸的芯片，直接嵌入到您的设备中。e SIM具有普通SIM 卡(SIM)的所有功能，存储您的订户资料并允许您的设备连接到蜂窝网络。然而，e SIM消除了对物理卡的需求，从而消除了SIM卡插槽的需要。
e SIM(SIM)技术的主要优势是其便利性。借助 e SIM，您可以在运营商或数据计划之间切换，而无需新的SIM卡。这意味着您无需再摆弄小卡片或寻找回形针来打开SIM卡插槽。相反，您可以直接从设备设置管理您的移动订阅。
领先的科技公司正在采用 e SIM技术。例如，苹果公司已将 e (Apple)SIM集成到其较新的 iPhone 机型、iPad Pro和Apple Watch中。谷歌的Pixel手机还采用 e SIM技术，而三星最新的Galaxy机型则提供物理SIM插槽和 e SIM插槽，以增加多功能性。
值得注意的是，虽然 e SIM技术具有许多优点，但它也有一些缺点。其一，并非所有运营商都支持 e SIM ，并且 e (SIM)SIM功能的可用性可能因地区和设备型号而异。此外，e SIM(SIM)的持久性在特定场景中可能是一个缺点。例如，如果您要出售手机，取出物理SIM卡比确保正确擦除和停用
e SIM 卡更容易。(SIM)
SD 卡的未来
正如我们所看到的SIM卡和 e (SIM)SIM的出现一样，SD 卡领域也即将迎来令人兴奋的新发展。技术(Technology)不断突破界限，扩展存储容量，并创造可以重塑我们处理数据存储方式的替代方案。
您可以购买的最大 SD 卡容量高达 1TB，提供巨大的存储空间，可以轻松容纳高分辨率照片、4K 视频、大量游戏文件等。想象一下，(Imagine)在比邮票还小的芯片中承载整个多媒体内容库。多亏了 microSD 卡，这就是我们今天生活的现实。
但即使我们目瞪口呆地看着现有的 1TB 卡，创新的视野仍在进一步延伸。我们已经看到了1.5TB SD(1.5TB SD)卡的发布。2TB原型 microSD 卡(2TB prototype microSD card)已经展示，展示了更显着的潜力。还有一个新的官方 SD 卡标准，称为SDUC（SD 超大容量(SD Ultra Capacity)），该标准承诺卡的大小高达 128GB。我们还没有找到这样的例子，但它确实描绘了未来几年 SD 技术的路线图。
超越 SD 卡
随着 SD 卡的不断发展，有朝一日可能取代它们的技术也在不断发展。例如，云存储近年来急剧流行。Google Drive、Dropbox和 Apple 的 iCloud 等服务提供充足的存储空间，可以从任何具有互联网连接的设备进行访问。优势？您不必担心物理存储卡丢失或损坏，并且可以轻松与他人共享您的文件。
然而，云存储也有缺点，只能部分抵消 SD 卡的需求。数据隐私、稳定的互联网连接要求以及持续的订阅费用等问题可能使 SD 卡成为许多人更实用的选择。
此外，内部设备存储的兴起是另一个需要考虑的因素。智能手机、平板电脑和笔记本电脑提供不断增加的内置存储容量，减少了对通过 SD 卡扩展存储的需求。SSD（固态硬盘(Solid State Drive)）技术不断降低内部存储的每GB价格，并且手机存储变得如此之大，以至于大多数人不再需要SD卡存储。这使得 SD 技术的可移动、便携和可交换特性成为其主要优势。
SIM Card vs. SD Card: What’s the Difference?
SIM cards and SD cards can indeed look similar to the untrained eye. Both cards are used in mobile phones and other mobile gadgets. However, they have different histories, purposes, and functions.
The Basics of SIM and SD Cards
A SIM card or Subscriber Identity Module is a microchip that securely stores your mobile phone number and cellular network subscription data.
It lets mobile phones make phone calls, send text messages (SMS), and use data services on a GSM cellular network. Mobile phones have a dedicated SIM card slot, and the card’s size can range from a full-size SIM to a nano SIM card.
An SD card, short for Secure Digital card, is a flash memory card used as additional storage for digital data. SD cards can range from standard SD to microSD or (rarely used) miniSD. They’re found in various electronic devices, including Android smartphones, digital cameras, and game consoles like the Nintendo 3DS and Switch.
The main difference between a SIM card and an SD card lies in its functions. A SIM card gives your device its identity, enabling it to make phone calls and send text messages. In contrast, an SD card is essentially a portable drive that can be inserted into various electronic devices to store data.
While some devices have separate slots for each card type, others, particularly smartphones, can use a combined slot. For example, some Samsung Galaxy models often have a hybrid slot where you can place two SIM cards (dual SIM functionality) or one SIM card and one microSD card for additional storage. However, this does not mean that SIM or SD cards have anything in common since these hybrid slots simply use clever engineering design to integrate both discrete standards.
Now that we have a good overview of SD and SIM cards, let’s have a closer look at each in turn.
SIM Cards: The Key to Mobile Connectivity
A SIM card is like your mobile phone’s passport. It identifies you to the mobile network, allowing you to place phone calls, send SMS or use apps like WhatsApp that require a mobile phone number. The tiny chip contains an International Mobile Subscriber Identity (IMSI) number and keys for encrypting voice and data traffic.
The SIM card has no storage capacity for photos, videos, or apps. However, it does store specific information like your phone number, SMS, and contacts, depending on the phone’s settings and mobile network.
SIM cards come in four sizes — full-size, Mini SIM, micro SIM cards, and nano SIM cards.
Now, there’s a good chance the “full-size” SIM you’re thinking of is the wrong one! These credit card-sized SIMs aren’t in use anymore, and the largest SIM card size you’ll still see is the Mini SIM, but even that is getting rare. It’s typical to get a 3-in-1 SIM package. these days with the mini, micro, and nano SIM sizes built into one card. You simply break out the size your device needs. The nano SIM has virtually no plastic material around the metal contacts, thanks to how much microchip technology has advanced.
Thanks to these modern nano sims, it’s possible to have compact dual-sim phone. This means you can have two different phone numbers or mobile network subscriptions on the same device; a handy feature for frequent travelers or those juggling work and personal numbers.
SD Card: Your Mobile Data Warehouse
An SD card’s primary function is data storage. It acts as an extension of your device’s internal storage, providing additional storage capacity for your files. You can use it to store data like photos, videos, apps, and other content on your Android phone or other devices that use SD card technology such as cameras.
Unlike a SIM card, an SD card doesn’t provide network functionalities or store your mobile phone number. Its only goal is to offer extra storage space. That’s why when you get a new phone, all your apps and media files can be transferred seamlessly if you’ve stored them on your SD card.
SD cards come in various storage sizes, from a few gigabytes to a whopping 1TB or more. Leading brands like SanDisk offer a range of SD cards readily available online from retailers like Amazon.
SD cards also come in different formats. Full-size SD cards are typically used in digital cameras and laptops, while microSD cards are more common in smaller gadgets like mobile phones. Devices without an SD card slot can still access SD card data using a USB card reader, assuming they have the requisite USB port.
SIM and SD Card Support in Android and iOS Phones
For Android phones, both SIM and microSD cards are frequently used together. This means you don’t have to worry too much about buying the biggest capacity Android phone you can afford, since you can always expand your storage.
On the other hand, SD cards are not nearly as reliable as your phone’s internal storage, and spontaneous SD card failure happens when you can least afford it. So always make backups!
Apple iPhones differ slightly. iPhones also use a SIM card for network capabilities. But instead of using a microSD card for additional storage, they rely solely on internal storage. This design choice is why you must carefully choose the storage capacity when purchasing an iPhone. On the upside, you will have much higher reliability and speed than an SD card, although Apple charges a significant premium for larger storage sizes.
From Mobile Phones to Other Devices
While SIM cards are mainly associated with mobile phones, SD cards have a broader range of applications. For example, digital cameras typically store high-resolution photos and videos with full-size SD cards. Game consoles like the Nintendo Switch use microSD cards to expand storage for games and saved data.
Moreover, some electronic devices use SD cards for operational purposes. A case in point is the Raspberry Pi, a mini-computer popular among DIY enthusiasts and educators, which uses an SD card to store the operating system and program files.
You will of course find SIM cards in devices that are not mobile phones. This includes USB cellular modems, laptops with built-in cellular functionality, iPads with cellular access, and even the Sony Vita had a cellular model.
eSims: The End of SIM Cards?
SIM cards have gone from credit card sized to the tiny nano size, and might now become essentially invisible. We’re seeing the transition from physical SIM cards to the latest technological innovation – the eSIM or embedded SIM.
So, what exactly is an eSIM? It’s a small, non-removable chip embedded directly into your device. The eSIM does everything a regular SIM does, storing your subscriber profile and allowing your device to connect to a cellular network. However, the eSIM eliminates the need for a physical card and, consequently, a SIM card slot.
The primary advantage of eSIM technology is its convenience. With an eSIM, you can switch between carriers or data plans without needing a new SIM card. This means no more fiddling with tiny cards or hunting for a paperclip to open the SIM card slot. Instead, you can manage your mobile subscription directly from your device settings.
Leading tech companies are embracing eSIM technology. Apple, for example, has incorporated eSIMs into its newer iPhone models, iPad Pro, and Apple Watch. Google’s Pixel phones also feature eSIM technology, and Samsung’s latest Galaxy models provide both a physical SIM slot and an eSIM for added versatility.
It’s worth noting that while eSIM technology offers many advantages, it also has a few drawbacks. For one, not all carriers support eSIMs, and the availability of eSIM functionality can vary by region and device model. Also, the permanence of eSIMs could be a disadvantage in specific scenarios. For instance, removing a physical SIM card is easier than ensuring the eSIM has been properly erased and deactivated if you’re selling your phone.
The Future of SD Cards
As we’ve seen with SIM cards and the emergence of eSIMs, the world of SD cards is also on the brink of exciting new developments. Technology continually pushes the boundaries, expands storage capacities, and creates alternatives that could reshape how we approach data storage.
The biggest SD card you can buy is a whopping 1TB, offering a vast reservoir of storage that could easily accommodate high-resolution photos, 4K videos, extensive game files, and much more. Imagine carrying an entire library of multimedia content in a chip smaller than a postage stamp. That’s the reality we’re living in today, thanks to microSD cards.
But even as we gawk at existing 1TB cards, the horizon of innovation is extending further. We’ve already seen the announcement of a 1.5TB SD card. And a 2TB prototype microSD card has already been showcased in an even more remarkable demonstration of potential. There’s also a new official SD card standard known as SDUC (SD Ultra Capacity) which promises cards up to 128GB in size. There have been no examples of this that we could find, but it does paint the roadmap for SD technology over the coming years.
Beyond SD Cards
While SD cards are evolving, so are the technologies that might someday replace them. For instance, cloud storage has surged in popularity in recent years. Services like Google Drive, Dropbox, and Apple’s iCloud offer ample storage space that can be accessed from any device with an internet connection. The advantage? You don’t have to worry about losing or damaging physical storage cards, and you can easily share your files with others.
However, cloud storage has drawbacks and only partially negates SD card needs. Issues like data privacy, a steady internet connection requirement, and ongoing subscription costs can make SD cards a more practical option for many people.
Additionally, the rise of internal device storage is another factor to consider. Smartphones, tablets, and laptops offer ever-increasing built-in storage capacities, reducing the need for expandable storage via SD cards. SSD (Solid State Drive) technology keeps bringing down the per-GB price of internal storage, and phone storage is becoming so large that most people won’t need SD card storage. This leaves the removable, portable, and swappable nature of SD technology as its main advantage.
